Short answer
No federal rule allows cannabis on a commercial flight. Cannabis sits in Schedule I of the Controlled Substances Act. TSA checks bags for threats to aviation security, not for drugs. Federal law covers airports and airspace. A state medical card or an adult-use license does not change the federal status of the plant.
What happens in practice varies. Some airports sit under state or local police control. Others fall under federal jurisdiction. A bag that draws attention goes to a law enforcement officer. That officer decides the next step.
What TSA does
TSA states on its site that officers do not search for marijuana or other illegal drugs. The same page states that officers refer a suspected illegal substance to a law enforcement officer. TSA does not arrest passengers. TSA does not charge a fee for drugs found in a carry-on.
TSA screens more than 2 million passengers on a typical day at US airports. Officers focus on items that can damage an aircraft or harm passengers.
Federal law
The Controlled Substances Act lists marijuana as a Schedule I drug. Schedule I means no accepted medical use under federal law and a high potential for abuse. Congress placed cannabis there in 1970. The listing has not changed since. DEA administers the schedule system.
Federal statute does not draw a line at a state border. Moving a controlled substance across a state line is a federal offense. A flight from one legal state to another legal state still crosses that line.
State law and airports
More than 20 states and the District of Columbia allow adult use. About 40 states allow some form of medical cannabis. State rules stop at the airport door where federal agencies hold jurisdiction. State and local police enforce state law at other airports.
Some airports in legal states publish statements that local police handle possession under state law. That does not protect a passenger on a connecting flight through Texas or another state with a strict ban.
Medical cannabis
Federal law has no medical cannabis exception. A state medical card does not authorize possession on an aircraft or in an airport under federal control. Prescription drugs are a separate category. TSA allows prescription medication in solid form in carry-on and checked bags after screening.
The FDA has approved one cannabis-derived drug, Epidiolex, for two rare forms of epilepsy. It is a controlled prescription, not a consumer cannabis product.
CBD and hemp
The 2018 Farm Bill removed hemp from the Controlled Substances Act. Hemp is defined as cannabis with 0.3 percent or less delta-9 THC on a dry weight basis. A CBD product made from hemp falls outside that federal ban if the THC level holds.
State law still applies. Some states ban CBD products that contain any THC. A label does not prove the THC level. A certificate of analysis from a lab is stronger evidence.
International flights
Cannabis remains illegal in most countries. US Customs and Border Protection officers inspect bags at ports of entry. Customs officers in other countries do the same on arrival. Canada legalized cannabis in 2018, but bringing cannabis across the US-Canada border is a crime in both directions.
Other countries impose fines or jail time. Several bar entry for a drug record.
Pilots and crew
The FAA prohibits pilots from operating an aircraft while under the influence of cannabis. Airmen must report drug and alcohol use on medical certificate applications. A positive test can end a pilot's job.
If an officer finds cannabis
Outcomes split by location. In a state with legal possession, the officer may release the passenger and return the bag. In a state with a ban, the officer may write a citation. Federal charges are possible at airports under federal control. A large quantity can raise the charge level.
Checklist before the flight
- Read the laws of the departure state, the arrival state, and every state on the route.
- Leave flower, edibles and concentrates at home if the route crosses a state with a ban.
- Carry prescription drugs in the original labeled container.
- Carry hemp CBD with a lab report showing THC at 0.3 percent or below.
- Do not pack cannabis in a checked bag or a carry-on for an international flight.